cleanup: remove v1.15.0 release since windows image build is broken

[andyzhangx]

What type of PR is this?
/kind cleanup

What this PR does / why we need it:
cleanup: remove v1.15.0 release since windows image build is broken

Which issue(s) this PR fixes:

Fixes #

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Special notes for your reviewer:

Release note:

none

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andyzhangx

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• OWNERS [andyzhangx]

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[k8s-ci-robot]

@andyzhangx: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-csi-driver-smb-sanity	fc1f456	link	true	/test pull-csi-driver-smb-sanity

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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[coveralls]

Pull Request Test Coverage Report for Build 9209801520

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 79.093%

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Totals
Change from base Build 9200774924:	0.0%
Covered Lines:	942
Relevant Lines:	1191

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💛 - Coveralls